As is well known, hair is composed of a unique protein material, called "keratin", which is distinguished by the fact that it contains a very significant amount of an amino acid (cystine) which contains the element sulfur in addition to the elements nitrogen, oxygen, carbon and hydrogen. In the structure of hair, the cystine covalently links adjacent polypeptide chains (K) through two sulfur atoms (S-S). These disulfide bonds can be broken only by specific chemical action.
Similarly, it is well established that in order to permanently wave hair this disulfide linkage must be broken. In this regard, many prior art compositions have been developed for the "cold permanent waving" of hair. Typically, these prior art systems treat the hair with a reducing agent which breaks the disulfide (cystine) linkages in the hair while the hair is wound around a curling rod. These prior art systems are typified by the disclosures in U.S. Pat. Nos. 2,479,382, 2,688,972, and 2,708,940.
As discussed in these prior art patents, the reducing agent typically employed is a mercaptan. The chemistry involved in the reaction of a mercaptan with the cystine disulfide bonds in the hair fiber is illustrated by the following chemical equation: EQU KSSK+2 RSH.revreaction.2 KSH+RSSR
By rebonding the sites in the reduced keratin in their new curled configuration, a permanent set which is impervious to water is established.
The rebonding of the reduced sites is accomplished by the action of a chemical oxidizing agent, commonly referred to as the permanent wave neutralizer. Typically, the oxidizing agent used in most neutralizers is hydrogen peroxide, and its chemical reaction is illustrated in the following equation: EQU 2 KSH+H.sub.2 O.sub.2 .fwdarw.KSSK+2 H.sub.2 O
A problem encountered with the use of mercaptan reducing agents for the permanent waving of hair is that one lotion strength is needed for normal hair while a different lotion strength is needed for damaged or difficult to wave hair. This problem is further compounded when there is damaged as well as normal hair on a head of hair to be permanently waved.
In general, damaged hair fibers and relatively undamaged hair fibers coexist on almost every head. Since the hair grows outwardly from the scalp, it is constantly being subjected to mechanical damage, particularly from the normal grooming process of shampooing, combing, drying, and brushing. In addition to this physical damage of hair, hair is also damaged by chemical action such as by exposure to sunlight and contact with water containing chlorine.
Damage to the hair fiber is almost entirely directed against the hair cuticle. In shampooing, for example, it is the actual physical manipulation of the hair, rather than the shampoo itself, which causes the majority of the damage. In normal hair, which has six to seven cuticle layers at the new growth or scalp area, studies have shown that a normal shampoo process can break away the cuticle at the rate of 1 to 2.5 cuticles for every fifty treatments. Since it is not unusual for a woman to shampoo her hair every day, it is therefore possible that she could lose up to seven cuticle layers of her hair in five months.
Since hair normally grows approximately one-half inch each month, it is apparent that in five months, all of the hair longer than two and one-half inches would be denuded of the cuticle layer. In addition, since the cuticle comprises ten percent or more of the hair fiber, and a much higher percentage in fine hair, and is intended to act as a protective sheath about the cortex, its complete destruction represents formidable damage to the hair fiber. Once the hair fiber has lost part or all of its cuticle, it is classified as porous and readily absorbs any aqueous solution applied to it.
During most permanent wave applications, a tress of the hair is wrapped around a cylindrical rod or curler. However, difficulty is often encountered in wrapping the free ends of the hair tress on the curler. Consequently, small square or rectangular pieces of paper, commonly referred to in the trade as "end wraps" are folded over the ends of the hair tress in order to make the hair controllable and easily rolled about a curler. Although end wraps are typically formed from paper or fabric material, various other compositions such as polyurethane foam and impermeable plastic foam are disclosed in such patents as U.S. Pat. Nos. 3,345,993 and 3,465,759.
Typical prior art cold permanent waving solutions have been unable to satisfy the diverse conditions which exist along the length of hair fiber to produce a uniform permanently waved head of hair. Typically, depending upon the concentration of the lotion applied to the head of hair, particular segments of the hair are either under processed or over processed.
Many prior art attempts have been made to eliminate the inherent difficulty encountered from the overprocessing and underprocessing of various segments of the hair during a permanent wave application. These prior art attempts included the application of various compositions to the end wrap in order to separately treat the portions of the hair fibers coming in contact with the end wraps. These prior art attempts included applying oils, perfumes, lanolin, diluted waving lotions, and vitamin compositions to the end wrap, all in an attempt to prevent the undesirable overprocessing of the hair ends. These prior art products are disclosed in U.S. Pat. Nos. 2,832,357; 2,839,066; 2,991,790; 3,087,501; 3,087,502; and 3,087,503.
In spite of the extensive effort directed to the protection of the hair ends in cold permanent waving procedures, none of these prior art systems have achieved the desired results. Consequently, continued over-exposure of the hair ends is typically encountered with the adverse appearance resulting therefrom.
Consequently, it is a principal object of the present invention to provide unique, saturated end wraps which prevent the overprocessing of hair ends during the application of a cold permanent wave.
Another object of the present invention is to provide unique, saturated end wraps having the characteristic features described above which produce a substantially uniform permanent wave throughout the head of hair regardless of the damaged condition of portions of the hair fiber.
Another object of the present invention is to provide unique saturated end wraps having the characteristic features described above which are easily employed, without special training, and with any cold permanent hair waving system.
Other and more specific objects will in part be obvious and will in part appear hereinafter.